Vacuum device for pulling a continuous web



y 7, 1954 w. A. STEWART 3,140,030

VACUUM DEVICE FOR PULLING A CONTINUOUS WEB Filed April 26, 1962 5Sheets-Sheet l esa9 July 7. 1964 w. A. STEWART VACUUM DEvicE FOR PULLINGA CONTINUOUS was 5 Sheets-Sheet 2 Filed April 26, 1962 INVENTOR. WAeeElvA 57'EWAET mum. 3 .3 M 3W M 3 mm. n W WW...

ATTOENEY July 7, 1964 w. A. STEWART VACUUM DEVICE FOR PULLING ACONTINUOUS WEB 5 Sheets-Sheet 3 Filed April 26, 1962 rrrib INVEN TOR.

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WAEEEN ,4. 575 wner vllllllll 0220 .J M kzs ATTORNEY July 7 1964 w. A.STEWART VACUUM DEVICE FOR PULLING A CONTINUOUS WEB 5 Sheets-Sheet 5Filed April 26, 1962 WARREN .4. STEWART kz'a ATTORNEY United StatesPatent 3,140,030 VACUUM DEVICE FOR PULLING A CONTINUOUS WEB Warren A.Stewart, Monkton, Md., assignor to Koppers Company, Inc, a corporationof Delaware Filed Apr. 26, 1962, Ser. No. 190,315 4 Claims. (Cl. 226-95)This invention relates to the manufacture of corrugated paperboard and,more particularly, to a device for applying a pulling force to acorrugated web'to draw the web in a longitudinal direction againstopposing forces such as friction forces acting on the web during theglue curing operation in the hot section.

In the manufacture of corrugated board, the fluted center element isfirst prepared, then attached to a liner in a gluing operation toproduce single-face board. This single-face is heated and after a secondgluing step is combined with a second liner in the double-backingoperation. The completed corrugated web is drawn through a curingoperation and finally slit into strips of the desired width and cut tothe desired length in a cut-off mechanism.

At that stage of the manufacturing sequence during which the secondliner is bonded to the single face in the double-backer, glue is appliedto the tips of the singleface flutes and the liner is pressed againstthe single-face. Because of the great speed of production of modernequipment employed in the manufacture of corrugated paperboard, it isvital that the curing of the glue bond between the single-face and theliner be accelerated substantially beyond its normal setting rate.

This acceleration can theoretically be produced by the application ofheat. In the modern double-backer the technique is to draw thecorrugated web over a long series of stearnheated plates andsimultaneously to apply pressure over the top side of the board by theuse of weight rollers which press down on a belt which in turn travelson top of the continuous web in order to avoid crushing the newly formedboard. The pressure is applied to urge the board toward the heatingplates with a force applied as uniformly as the pressurizing equipmentis capable of exerting. By this action better heat transfer is promoted,a uniform joint structure is produced and a stiff, unwarped boardresults.

Considerable heat must be applied to effect acceleration of the curingof the glue bond. Further, this heat must be gradually applied and, as aresult, the series of hot plates over which the board is drawn duringthe curing operation is as a general rule about 40 feet in length. Greatforce must be applied to pull the web of corrugated board over this 40feet of steamheated plates particularly in view of the frictiongenerated between board and plates by the downward force of the weightrollers.

At the present time, newly fabricated corrugated board is pulled throughthe glue curing, or hot, section by sandwiching the board between a pairof continuous belts, one above and one below the web. These belts are soadjusted relative to the web so that only a light pressure istransmitted from the belts to the surface of the corrugated board toavoid crushing it. As these belts are driven, the friction force betweenthe belts and the board serves to pull the board through the hotsection. Since only a light pressure, in the order of 0.125 p.s.i., canbe safely applied to opposite faces of the board to urge the two beltstoward each other to grasp the board, it becomes necessary to offsetthis light pressure by applying the pressure over an extremely largearea to generate sufficient over-all force.

Experience has shown that a gripping surface the width of the board andabout 40 feet in length is required to ice pull the web at the speedsrequired in modern production, speeds in excess of 600 feet per minute.Of necessity, therefore, in addition to the expense of the equipmentinvolved, a large amount of floor area remains occupied by the immensemachine required at present for executing the pulling operation.

It is, therefore, an object of the present invention to provide a devicefor applying a pulling force to a cor- 'rugated web, which deviceemploys a substantially greater contact pressure between the device andthe web yet occupies a much smaller floor area.

Another object of the present invention is the provision of means forutilizing vacuum pressure for applying a pulling force to a corrugatedweb.

A further object of the present invention is the provision of a devicefor applying apulling force to a continuous web by the use of a vacuumbelt free of unbalanced forces acting normal to its contacting surface.

Still another object of the present invention is the use of a speciallyconstructed vacuum belt for applying a pulling force to a continuous webwhile positively synchronizing the speed of the vacuum belt with thespeed of the head roll driving the vacuum belt.

Still a further object of the present invention is the provision of aspecially constructed vacuum belt by which extremely high pulling forcesmay be exerted by relatively small head rolls driving the vacuum belt.

These objects are realized in the present invention by the use of ahollow belt assembly with one face thereof in contact with thecontinuous web to be pulled at some point beyond the glue curingstation, means for positively driving said belt assembly, openingsproviding communication from the hollow interior of the belt assembly tothe surface of the belt assembly in contact with the continuous web,support means receiving said belt assembly thereon, means connected withthe interior of said belt through said support means for exhausting airtherefrom to create a vacuum therein whereby the continuous web isforced into contact with a surface of the belt by atmospheric pressure.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings in which like referencenumerals designate like parts throughout the figures thereof andwherein:

FIGURE 1 is a schematic representation of the present invention embodiedin the equipment employed in performing the sequence of operations forthe manufacture ofcorrugated paperboard,

FIGURE 2 is a plan view of a preferred embodiment of the presentinvention with portions thereof cut away to show internal details ofconstruction,

FIGURE 3 is an enlarged elevational view of the vacuum assembly of theembodiment shown in FIGURE 2 with portions of the view cut away to showinternal construction,

FIGURE 4 is an enlarged sectional view taken on line 4-4 of FIGURE 2,

FIGURE 5 is a plan view of a second embodiment of the present inventionwith portions thereof cut away to show internal details of construction,

FIGURE 6 is an enlarged elevational view of the vacuum assembly of theembodiment shown in FIGURE 5 with portions of the view cut away to showinternal details of construction,

FIGURE 7 is an enlarged sectional view taken on line 7--7 of FIGURE 5,

FIGURE 8 is a plan view of a third embodiment of the present invention,

FIGURE 9 is an enlarged elevational view of the vacu- 3 um assembly ofthe embodiment shown in FIGURE 8 with portions of the view cut away toshow internal details of construction,

FIGURE 10 is an enlarged sectional view taken on line 10-10 of FIGURE 8,

FIGURE 11 is a plan view of a fourth embodiment of the presentinvention,

FIGURE 12 is an enlarged elevational view of the vacuum assembly of theembodiment shown in FIGURE 11 and FIGURE 13 is an enlarged sectionalview taken on line 1313 of FIGURE 11.

In FIGURE 1 at the right hand side thereof is illus' trated the sequenceof forming the single-face. Stock strip 11, having been previouslytreated with steam is passed between toothed corrugator roll 12 andtoothed corrugator roll 13 complementary therewith whereby corrugationsor flutes are impressed in strip 11. After fluted strip 11 passes aroundroll 13, adhesive is applied to the outer tips of the flutes by doctorroll 14 which, as it rotates, picks up adhesive from pot 16.

As fluted strip 11 having adhesive applied thereto passes over roller17, the outer tips of the flutes in strip 11 are brought into contactwith liner 18 whereby these components are firmly joined to producesingle-face web 19.

Single-face web 19 advances over idler roll 21, over the heating surfacein steam chest 22, and past glue station 23 for initiation of thedouble-backing operation. As shown, single-face 19 is united with secondliner 24 coming from roll 26 to produce the double-face board 27. Thennewly formed board 27 is drawn over the heating surface in steam chest28 which comprises a long series of steamheated plates (not shown).Pressure and heat are simultaneously applied to cure the doublefaceassembly, the requisite pressure being supplied by a series of weightrollers 29 which press down on the top side of belt 31 disposed over andtravelling in contact with the top side of the double-back board 27Steam chest 28 (or similar heating surface) is typically about 40 feetin length to supply heat at the requisite rate and intensity.Considerable dragging friction must be overcome to pull board 27 overthe 40 foot series of hot plates particularly in view of the pressure ofweight rollers 29 urging board 27 against the surface of these plates.

In the pull-off mechanism employed at present for pulling board 27through this heating stage the requisite force is supplied by a deviceabout 40 feet in length primarily comprising a pair of opposed drivencontinuous belts. These belts are disposed to receive the newlycompleted board between their opposed faces applying light pressurethereto so as to avoid crushing the board and to pull the board throughthe hot section by the friction forces applied between the belts and theboard. As explained above, the total friction force required to pull thecorrugated board through the hot section is substantial and can only besupplied in the prior art pull-off apparatus by the use of large contactarea between the belts and the board since the friction force per unitarea must remain at an extremely low value.

In place of the opposed driven continuous belts employed at present, thevacuum pull-off apparatus 32 provides a mechanism whereby about 40 timesas much force per unit area can be applied to board 27 without damagethereto. As a result of its capacity to safely apply a force per unitarea far in excess of that possible with the prior art opposed beltdevice, the requisite pulling force can be supplied by a compactstructure the total length of which need not exceed about 7 feet.

As a method of comparing the effectiveness of the improved pull-oifmechanism disclosed herein with the pulling device employed at presentin the industry, the following calculations are indicative. By the useof pressure having a value of atmospheric pressure or less to press thedouble-face board 27 against the contact surface of vacuum pullingdevice 32, contact pressures between board and surface of up to about 10psi. can be economically and safely maintained with the improvedpull-01f mechanism as opposed to the present arrangement wherein amaximum pressure of approximately 0.125 p.s.i. can be safely applied.

It is reasonable to assume that the coeificient of friction (a) willremain essentially constant in comparing the two devices, therefore, theimproved pulling force per square inch is represented by F=,u.X10. Thepresent pulling force would be represented as F'=,l/.X2X0.125=.25,u..Comparing F and F, F=l0/.25 or F=40F'.

Although the above-expressed mathematical relationship demonstrates theapproximate maximum value of pulling force which can be produced withthe present invention, an application of about 4 lbs. of net pressure isused in practical applications instead of the 10 psi. employed in thecalculations. As a result a pulling force of perhaps 16 times thepresent force for comparable lengths of pulling apparatus is produced.

FIGURES 2, 3 and 4 show in greater detail the preferred embodiment ofthe present invention. The web of corrugated board 27 after leavingsteam chest 28 passes over the upper surface of driven continuousperforated belt 33 or a plurality of such belts as shown in the planview of FIGURE 2 to accommodate a very wide web.

As is shown in the cut-away portions of FIGURE 3 this belt 33 isprovided with cleats 34 whereby belt 33 is positively driven by thetoothed head rolls 36 and 37 maintaining positive synchronism betweenthese head rolls and belt 33. By a novel method and mechanism which willbe more completely described below firm contact is maintained betweenboard 27 and belt 33 eliminating slip therebetween. Having eliminatedslip, the positive synchronism between head rolls 36, 37 and board 27enables an accurate indication of the speed of board 27 by a measure ofthe speed of rotation of the head rolls by conventional speed measuringdevices,

Briefly described, the novel method and mechanism operate in thefollowing manner: during movement by the upper run of belt 33 in thedirection of travel of board 27 belt 33 leaves head roll 36 and isbrought into contact with the upper surface of flat continuous belt 38which in turn contacts portions of the surface of support table 39. Inthis manner, belt 33 joining with and acting in combination with fiatcontinuous belt 38 as a vacuum belt assembly converts the spaces betweencleats 34 into a plurality of substantially closed chambersinterconnected by common plenums. When a vacuum is created in thissubstantially closed system the portion of board 27 over belt 33 isforced firmly against moving perforated belt 33 under the pressure ofthe atmosphere and as the upper run of belt 33 moves forward driven byhead rolls 36 and 37, board 27 is forced to move together with belt 33.As any given part of the portion of board 27 held against belt 33 ismoved past the downstream end (right end in FIGURE 3) of support table39 and thereby out of the vacuum zone, the vacuum under this small partof board 27 is destroyed and the force urging board 27 and belt 33together at this point is likewise removed permitting board 27 and belt33 to separate and be conducted along their separate paths.

The vacuum referred to above is produced by the coaction of severalelements in a novel fashion hereinafter described in greater detail. Fanor vacuum pump 41 is employed to exhaust air from plenum 42 which inturn receives air through conduits 43, 44, 46 and 47 from thelongitudinal-extending table plenums 48, 49, 50 and 51 located beneathbelt 38. Valves 43a, 44a, 46a and 47a are provided to disconnect eitherof the two pull-off belts 33 (shown disposed side by side) from theevacuating mechanism when that particular belt is not in use.

Belt 33 is formed with solid rims 52 extending the full length of thebelt along either side thereof. The cleats 34 extend laterally of belt33 between these rims 52. As the laterally-extending tooth spaces 53between cleats 34 of belt 33 move into the vacuum zone over supporttable 39 during the rotation of belt 33, the undersides of rims 52 arebrought into contact with the flat upper surface of belt 38 therebyconverting spaces 53 into substantially closed chambers.

Head rolls 54 and 56 each having a plane surface drive the fiat belt 38at the same velocity as belt 33 is driven by toothed head rolls 36, 37thereby eliminating relative motion between belts 38 and 33. Belt 38moves with the under surface thereof in contact with ridges 39a ofsupport table 39 and bridging over plenums 48, 49, 50 and 51 with theupper surface thereof in contact with the undersides of rims 52 andcleats 34. During this passage the edges or side surfaces of both belts33 and 38 pass adjacent to upwardly extending portions 57, 58 and 59 ofsupport table 39 without the necessity of very close clearances, sincethe vacuum is drawn from below belt 38.

In order to create the required vacuum table plenums 48, 49 and 50, 51communicate with substantially closed chambers 53 via slots 60 whichpass through belt 38. In this manner, the network of interconnectedconduits and chambers comprises a substantially closed volume from whichair may be exhausted by pump 41 through plenum 42 and conduits 43, 44,46 and 47.

To create the vacuum in the desired location, which is between belt 33and board 27, belt 33 is provided with perforations or holes 61 whichpenetrate its upper surface and communicate with chambers 53. The uppersurface of belt 33 is constructed of a special layer of rubher orsimilar material into which a network of grooves 62 have been cutextending longitudinally and laterally of belt 33. By thismeans anentire network of localized zones lying between belt 33 and board 27 areevacuated whenever openings 53 have air withdrawn therefrom via openings61 extending between grooves 62 and openings 53.

Thus, as any given opening 53 passes over support table 39 at the lefthand end thereof (as viewed in FIG- URE 3), this opening or space isconverted into a substantially closed chamber forming an integral partof a substantially closed volume as a result of the cooperativepositioning of belts 33 and 38 and the communication provided by slots60 in register with table plenums 48, 49 and/or 50, 51. As this givenopening 53 continues to move to the right under the driving action ofhead rolls 36 and 37 this substantially closed volume including opening53 is subjected to the action of pump 41 which through plenum 42,conduits 43, 44 and/ or 46, 47, table plenums 48, 49 and/or 50, 51 andslots 60 exhaust air therefrom. Air is in. turn drawn in through holes61 from the network of grooves 62 thereby withdrawing the air frombetween board 27 and belt 33 and creating the desired vacuum.

Those chambers 53 which are not provided with holes 61 to communicatedirectly with the upper surface of belt 33 are still. able to functionto provide passage for the air being exhausted and aid in the formationof the necessary vacuum because of the individual length and staggeredarrangement of slots 60 for by this means all chambers 53 areinterconnected by the longitudinally extending table plenums commonthereto.

When a vacuum is developed in the network of grooves 62 between board 27and the surface of belt 33, the pressure of the atmosphere provides avery large force which pushes board 27 against the upper surface of belt33. As a result, the entire assembly of belts 33 and 38 (referred to asthe vacuum belt assembly) is forced down. Ridges 39a of table 39 providea reduced area of contact to minimize the friction force between thevacuum belt assembly and table 39. Also preferably the grooves 64 areextended to the far ends of table 39 and communicate with theatmosphere. With this arrangement, the generation of undesirable heat asa result of friction between the surface of support table 39 and thevacuum belt assembly is greatly reduced.

By the use of this novel mechanism, as belt 33 is positively advanced bytoothed head rolls 36 and 37, a very high tensile force is transmittedto web 27 to supply the necessary pull to draw board 27 through the hotsection. The magnitude of the pulling force which can be applied will,of course, depend upon the differential in pressure between atmosphericpressure and the vacuum created in the network of grooves 62, chambers33 and table plentuns 48, 49, 50 and 51. g

It is important to note that since the flutes of the corrugated board 27are perpendicular to the direction of board travel, air is free to enterthe flutes of the corrugated web from either side and consequently thepressure of the atmospheric air on the corrugated web will be appliedonly to the lower liner. As a result no force other than normal airpressure will be exerted on the upper surface of board 27 and crushingof the board is avoided.

Since, in the dual opposed belt web-pulling device which is used at thepresent time, the corrugated board frequently slips with respect to themoving belts and the belts also slip with respect to the rolls employedto drive them, the simple expedient of measuring the speed of the driveroll to detect the speed of the moving web is unable to provide anaccurate measure of board speed. Complex mechanisms have been proposedto accurately detect web speed to enable cutting of the web into preciselengths. The present invention, on the contrary, positively synchronizesbelt speed (and, therefore, board speed) with the speed of the head rolldriving the belt by the use of a cleated belt. Also, because of thepositive nature of the drive the present invention enables the use ofsmaller head rolls to exercise extremely high pulling forces. Otherspecially constructed belts using the same principle and constructed ofvarious materials may be employed so long as the requisite positivedrive between head roll and belt are maintained.

Instead of employing the two-belt vacuum belt assembly system shown inthe preferred embodiment, a singlebelt vacuum belt assembly may be used.Such a mechanism is illustrated in FIGURES 5, 6 and 7 as a secondembodiment of the present invention. By eliminating the second belt, thesmooth head rolls 54 and 56 and their driving mechanism are alsoeliminated. In all other respects, the operation of the device shown inFIG- URES 5, 6 and 7 is analogous to the description already given abovefor the preferred embodiment.

The upper surface of belt 33 in this embodiment is substantiallyidentical to the upper surface of belt 33 in the preferred embodiment.However, as is more clearly seen in FIGURE 7, the arrangement of cleats34 for the belt 33 is different. Cleats 34 are formed only along therims 52 of belt 33 and these cleats project into recesses 66 provided inthe surface of table 39. In this construction, the volume to theunderside of board 27 to be evacuated consists solely of the network ofgrooves 62, holes 61, longitudinally extending table plenums 48, 49, 50and 51, conduits 43, 44, 46 and 47 and plenum 42 which is evacuated bypump 41.

As in the preferred embodiment grooves 64 are provided in the surface oftable 39 in contact with the underside of belt 33 to minimize thefriction force by limiting the area of table 39 in contact with belt 33to that of ridges 39a. These grooves 64 are preferably extended to thefar ends of table 39 to communicate with the atmosphere.

Still a third embodiment of the present invention is illustrated inFIGURES 8, 9 and 10. This embodiment and the fourth embodiment shown inFIGURES 11, 12 and 13 withdraw air from the sides of the vacuum beltassembly rather than from beneath the belt assembly as in the previousembodiments.

In order to provide for the removal of air from the side of the assemblycleats 34 extend transversely from edge to edge of the cleated belt 33employed in this embodiment. As the upper run of belt 33 passes into theevacuation zone the underside of belt 33 is brought into juxtapositionwith the upper side of fiat, imperforate continuous belt 38 over supporttable 39 in the manner illustrated in the preferred embodiment therebyconverting openings 53 between cleats 34 into open-ended chambers. Theedges or side surfaces of the vacuum belt assembly formed by juxtaposedbelts 33 and 38 pass with relatively small clearance adjacent upwardlyextending portions 57, 58 and 59 of support table 39. Table plenums 48,49, 50 and 51 are formed in portions 57, 58, 59 disposed injuxtaposition with the open ends of spaces or chambers 53.

In this manner, a substantially closed volume consisting of chambers 53interconnected by table plenums 48 and 49 or 50 and 51 are produced fromwhich air is exhausted by pump 41 through conduits 43, 44, 46, 47 andplenum 42.

As in the previous embodiments, holes 61 are provided penetrating theupper surface of belt 33. These holes communicate with chambers 53 onthe one hand and the network of grooves 62 on the other hand.

In all other respects the operation of this device is analogous to thedescription already given for the preferred embodiment. However, inorder to insure a minimum of friction force between the underside of thevacuum belt assembly and the upper surface of support table 39, holes 63are provided in table 39 to conduct atmospheric pressure to theunderside of the belt assembly.

The fourth embodiment shown in FIGURES 11, 12 and 13 substitutes asingle component vacuum belt assembly for the two-component vacuum beltsystem employed in the embodiment in FIGURES 8, 9 and 10.

Air is withdrawn from the edges of the belt assembly in the manner shownand the upper surface of belt 33 in this embodiment is identical to theupper surface of the other embodiments. However, as shown in the cutawayview in FIGURE 12, the interior of belt 33 is hollow being provided withlateral ribs 71 at intervals to insure structural integrity and also todefine a plurality of open-ended laterally-extending chambers 72.

In this embodiment cleats 34 are provided solely to provide therequisite positive synchronization between the movement of belt 33 andtoothed head rolls 36, 37. As shown in FIGURE 13, the longitudinallyextending table plenums 48, 49, 5t and 51 are so located in theupwardly-projecting portions 57, 58, 59 of table 39 that as open-endedchambers 72 pass over the fiat supporting surface of table 39, thesechambers 72 are placed in juxtaposition with the table plenums. Sinceupwardlyextending table portions 57, 58 and 59 also close the ends ofinter-toothed spaces 53 between cleats 34 in that portion of the belt injuxtaposition therewith, provision must be made to vent all suchopenings 53 to the atmosphere. This venting is provided by holes 63 incommunication with longitudinal slots 73 extending the length of table39 as shown in FIGURE 13. A vacuum is created in grooves 62, holes 61,chambers 72, and table plenums 48, 49, 50 and 51 via conduits 43, 44,46, 47 and plenum 42 by pump 41.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is, therefore, to beunderstood, that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. Apparatus for successively applying a pulling force to advancesubsequent portions of a continuous web against opposing forcescomprising in combination (a) a continuous belt assembly driven in afixed path,

(1) said belt assembly comprising a continuous cleated belt and acontinuous smooth belt, said smooth belt having the outer surfacethereof in contact with the ends of a plurality of the inwardly-directedcleats of said cleated belt,

(2) said continuous belt assembly being located along the path ofadvance of said web, said path being linear at least in part,

(b) a portion of said web being in contact with the surface of saidcontinuous belt assembly,

(0) drive means in engagement with said continuous belt assembly forcontinuously driving said continuous belt assembly in said fixed path,and

(d) evacuating means in juxtaposition with said continuous belt assemblyfor evacuating gas from that area of said surface contiguous with saidportion of said web while said continuous belt assembly is in motion.

2. Apparatus substantially as recited in claim 1 wherein the contact ofsaid inwardly-directed cleats and the surface of said smooth beltprovides a plurality of interior chambers and said cleated belt has aplurality of passageways therethrough connecting said chambers with theouter surface of said belt.

3. Apparatus substantially as recited in claim 2 wherein the evacuatingmeans comprises a housing enclosing a plenum, said plenum providingintercommunication between the interior chambers, a pump and acollecting system connected between said pump and said plenum.

4. Apparatus substantially as recited in claim 2 wherein the chambersare open-ended and extend laterally through the belt assembly and oneplenum is aligned along each edge of said belt assembly in juxtapositionwith and communicating with the open ends of a plurality of saidchambers.

References Cited in the file of this patent UNITED STATES PATENTS1,077,399 Droitcour Nov. 4, 1913 1,118,552 Honiss Nov. 24, 19141,610,818 Spadone et al. Dec. 14, 1926 1,954,098 Powers Apr. 10, 19342,425,210 Stokes Aug. 5, 1947 2,731,262 Morrow Jan. 17, 1956 2,753,181Anander July 3, 1956 2,852,255 Fischer Sept. 16, 1958 2,954,911Baumeister et al Oct. 4, 1960 2,987,314 Monaghan June 6, 1961 3,057,529Fitch Oct. 9, 1962

1. APPARATUS FOR SUCCESSIVELY APPLYING A PULLING FORCE TO ADVANCESUBSEQUENT PORTIONS OF A CONTINUOUS WEB AGAINST OPPOSING FORCESCOMPRISING IN COMBINATION (A) A CONTINUOUS BELT ASSEMBLY DRIVEN IN AFIXED PATH, (1) SAID BELT ASSEMBLY COMPRISING A CONTINUOUS CLEATED BELTAND A CONTINUOUS SMOOTH BELT, SAID SMOOTH BELT HAVING THE OUTER SURFACETHEREOF IN CONTACT WITH THE ENDS OF A PLURALITY OF THE INWARDLY-DIRECTEDCLEATS OF SAID CLEATED BELT, (2) SAID CONTINUOUS BELT ASSEMBLY BEINGLOCATED ALONG THE PATH OF ADVANCE OF SAID WEB, SAID PATH BEING LINEAR ATLEAST IN PART, (B) A PORTION OF SAID WEB BEING IN CONTACT WITH THESURFACE OF SAID CONTINUOUS BELT ASSEMBLY, (C) DRIVE MEANS IN ENGAGEMENTWITH SAID CONTINUOUS BELT ASSEMBLY FOR CONTINUOUSLY DRIVING SAIDCONTINUOUS BELT ASSEMBLY IN SAID FIXED PATH, AND (D) EVACUATING MEANS INJUXTAPOSITION WITH SAID CONTINUOUS BELT ASSEMBLY FOR EVACUATING GAS FROMTHAT AREA OF SAID SURFACE CONTIGUOUS WITH SAID PORTION OF SAID WEB WHILESAID CONTINUOUS BELT ASSEMBLY IS IN MOTION.